This invention relates in general to the field of medical devices, more particularly, this invention relates to a flexible elongate member such as a medical guide wire or catheter having one or more electrical contacts.
Flexible elongate members used in medical applications such as guide wires, catheters, etc., which have electrical devices (e.g., pressure sensors, ultrasound transducers, pressure flow measurement devices, etc.) need to have one or more electrical contacts typically close to the proximal end of the member. The electrical contacts allow for the electrical interconnection of the electrical device found on the flexible elongate member, for example, a pressure sensor, to an external monitoring apparatus.
Currently there is some difficulty in manufacturing small electrical contacts on flexible elongate members such as guide wires having a diameter in the order of 0.018 inch or less. In FIG. 1 there is shown a prior art guide wire 100 having an electrical device in the form of a pressure sensor 110 located in proximity to the distal end of the guide wire 100. Pressure guide wire 100 includes a plurality of electrical contacts 104 separated by insulator bands (spacers) 116 which help form a cylindrical connector located close to the proximal extremity 102 off the pressure guide wire 100. These electrical contacts 104 are electrically interconnected to pressure sensor 110 and allow for the connection of the pressure sensor to an external monitoring apparatus.
The pressure guide wire 100 further includes a shaft also referred to as a hypotube 106 typically formed of stainless steel, a flexible coil member 108 located on one side of the pressure sensor 110, a radiopaque coil 112 located on the other side of pressure sensor 110, and a tip 114. The pressure sensor 110 is electrically interconnected to contacts 104 via a plurality of electrical conductors (not shown), which run through the inside of the flexible coil 108 and shaft 106.
The cylindrical guide wire connector formed by contacts 104 is interconnected to a female connector 200 shown in FIG. 2. The proximal end 102 of pressure wire 100 is inserted in to the nose section 206 of connector 200 such that contacts 104 become electrical coupled to corresponding contacts located inside of the swivel head 204. The other end of connector 200 includes a pin plug 202, which interconnects to an appropriate monitoring apparatus, in this case a pressure monitor (not shown). In use, the distal end of pressure wire 100 is inserted into a vessel (e.g., artery) of a patient in order to measure the pressure at certain locations along the vessel, which is under investigation.
One problem with pressure guide wire 100 is that the individual electrical contacts 104 are very difficult and expensive to integrate into the guide wire. Contacts 104 are individual metal bands, which are separated by non-electrically conductive spacers 116. During manufacture, each of the individual contacts 104 have to be soldered to the appropriate electrical conductor (not shown, e.g., electrical wire), which is attached to pressure sensor 110.
After the appropriate electrical conductor is soldered or welded to its corresponding contact 104, each individual contact has to be adhesively bonded to the rest of the guide wire 100. The spacers 116 also have to be individually inserted and bonded to the adjacent contact(s) 104. The bonding of the spacers 116 and contacts 104 causes further problems in that the adhesive which bonds them together tends to seep between the joints and has to be removed from the exterior portions of the proximal end of the guide wire 100. Given the small size of the guide wire 100, all of these time consuming steps have to be performed by assembly workers using microscopes which further increase the opportunity for manufacturing mistakes to occur.
Problems can also occur with the contacts 104 or spacers 116 becoming separated from the rest of the assembly due to bad bonding of a particular contact 104 or spacer 116. Another manufacturing problem occurs with the solder joints, which interconnect the electrical conductors coming from pressure sensor 110 to the individual contacts 104. Given that the electrical conductors have to be soldered to the inside surface of the contacts 104, there is very little room in which to solder the contact with a soldering tool, thus some bad solder joints can occur during production.
A need thus exists in the art for a contact assembly, which can overcome the problems associated with the prior art mentioned above.